1. Field of the Invention
This invention pertains generally to a unique on-axis monolithic ellipsoidal lens and particularly to its application in and for optical coupling systems. More specifically, the invention describes a lens form adapted to function as a compact collection lens with finite conjugates to couple the collected energy from a broadband source into a multi-mode optical fiber.
2. Description of the Related Art
This invention relates generally to catadioptric systems. Catadioptric optical systems combine reflection and refraction in the same optical system, typically via lenses (dioptrics) and curved mirrors (catoptrics). Catadioptric combinations are widely used in focusing systems, including telescopic focusing systems and are often associated in this format with the pioneering work of Dmitri Dmitrievich Maksutov, the inventor of the Maksutov telescope.
Other prior art examples that are or might be related to the technology and/or purposes of the instant invention include: (1) U.S. Pat. No. 2,571,657 issued to Bennett for a “Catadioptric Lens System” (1951) and describing catadioptric systems having large relative apertures and wide angular fields; (2) U.S. Pat. No. 3,001,446 issued to Bouwers for “Optical Systems Comprising a Spherical Concave Mirror and a Meniscus Lens” (1961) and describing catadioptric systems having large relative apertures and wide angular fields; (3) U.S. Pat. No. 3,982,824 issued to Rambauske for a “Catoptric Lens Arrangement” (1976) and describing species of catoptrics lens arrangements characterized by use of a quadratic conic mirror having real or virtual focal points displaced from a lens axis: (4) U.S. Pat. No. 5,042,928 issued to Richards for a “Parallel Catadioptric Optical Element” (1991) and describing a single hybrid optical element combining reflective and refractive imaging utilizing a dual reflector outer annulus zone and a refractive inner zone to achieve a high numerical aperture: (5) U.S. Pat. No. 5,301,249 issued to Hamblen et al. for a “Catoptric Coupling for an Optical Fiber” (1994) and describing a device for coupling a laser diode emission to an optical fiber utilizing two opposed mirrors to redirect the divergent light beam of the laser diode to within the smaller numerical aperture or angle of acceptance of the optical fiber: (6) U.S. Pat. No. 5,473,474 issued to Powell for a “Panoramic Lens” (1995) and describing a panoramic imaging system having a panoramic imaging block with a concentric axis of symmetry, two refractive surfaces and two reflective surfaces: (7) U.S. Pat. No. 5,930,055 issued to Eisengerg for a “Lens Apparatus” (1999) and describing a unitary, at least partially dielectric, element having formed thereon plural electromagnetic radiation reflecting surfaces, at least one of which is a total internal reflection surface: and (8) U.S. Pat. No. 6,896,381 issued to Benitez et al. for a “Compact Folded-Optics Illumination Lens” (2005) and describing an apparatus configured to convert a first distribution of an input radiation to a second distribution of output radiation.
The foregoing art examples and/or disclosures reveal a variety of forms and systems. However, none feature the unique combination of elements and advantages offered by the instant invention.